Well, since your plants are still pretty young (1-2 weeks), they arn't ready for all the nutes you want them to take. I usually add nutes to my water every other watering, not every time. And until they develop a strong root system, a large stem and more leaves, you should add only half of the quantity of nutes that your product instructs you to (ex: mine says to add 1 filled bottle cap/2l so until my plant is 3-4 weeks old I add 1/2 a bottle cap/2l). Right now, as a first precaution, at your next watering don't give it any nutes in order to flush the soil a bit of any excess nutes that may continue to burn your plant.
Keep us posted on your plant's evolution.
PS: maybe you know this, but if you don't, fest you find out: You don't need to water your plants very often (adding nutes very often will also cause nute burn). You need to enough water so that there will be just a little in the pan under the pot. You need to wait for the soil on the surface to dry out until you can water again. Best way to find out is to stick your finger 1-2cm in the soil and feel if it's moist or not. If it doesn't feel too moist or your soil feels pretty dry, water again.